The present disclosure relates generally to the manufacturing of semiconductor devices, and more particularly to a self-assembled photosensitive layer that may be used in immersion lithography.
As semiconductor fabrication technologies are continually progressing to smaller feature sizes such as 65 nanometers, 45 nanometers, and below, immersion lithography methods are being adopted. However, during an exposure process using an immersion lithography system, contaminations such as particles and water residues can be introduced into the immersion lithography system and further contaminate semiconductor wafers to be processed therein. For example, leaching of photoresist materials into the immersion fluid may cause such contaminations. Accordingly, the contaminations can cause defects and yield degradation.
One method for reducing such contamination is to provide a topcoat layer directly over the photoresist. The topcoat layer provides a barrier to prevent diffusion of photoresist material into the immersion fluid. However, such a method possesses a number of shortcomings. First, the costs and time associated with forming the topcoat layer are extensive. Second, the topcoat layer may adversely affect the lithography process due to its refractive index, thickness, and chemical makeup. Therefore, what is need is a simple and cost-effective material and method for an improved photosensitive layer for use in immersion lithography.